Apparatus and method for signaling in a wireless communication system

ABSTRACT

A method of signaling in a wireless communication system ( 300 ) comprising a first network element ( 310 ) serving a wireless communication unit ( 325 ) with at least one packet data network (PDN) connection. The method comprises transmitting, by the first network element ( 310 ) to the wireless communication unit ( 325 ), a signaling message relating to a wireless communication unit ( 325 ) uplink (UL) PDN transmission, where the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.

FIELD OF THE INVENTION

The invention relates to apparatus and methods for signalingcommunications in a packet data network, such as a 3^(rd) GenerationPartnership Project (3GPP) cellular communication system.

BACKGROUND OF THE INVENTION

Currently, 3rd generation cellular communication systems are beingrolled out to further enhance the communication services provided tomobile phone users. The most widely adopted 3rd generation communicationsystems are based on Code Division Multiple Access (CDMA) and FrequencyDivision Duplex (FDD) or Time Division Duplex (TDD) technology. Furtherdescription of CDMA, and specifically of the Wideband CDMA (WCDMA) modeof UMTS, can be found in ‘WCDMA for UMTS’, Harri Holma (editor), AnttiToskala (Editor), Wiley & Sons, 2001, ISBN 0471486876.

In 3GPP systems, such as the General Packet Radio System (GPRS), EvolvedPacket System (EPS), the downlink communication endpoint, namely themobile or handheld wireless communication unit, referred to as userequipment (UE) in 3G parlance, may have multiple simultaneousconnections to a number of network elements.

Such network elements typically comprise gateways (GWs), such as GeneralGPRS Support nodes (GGSNs), packet data network (PDN) GWs, etc., inorder to obtain access to different Packet Data Networks (PDNs) thatfacilitate the UE accessing a number of different services (for examplefacilitating access to corporate services as well as simultaneous accessto the Internet).

In such systems, the amount of data being transferred between elementsmay be controlled by setting an aggregate maximum bit rate (AMBR), whichis defined as an upper limit for non-guaranteed bit rate (GBR)communication bearers that are associated with a particular PDNconnection that a UE has established.

FIG. 1 illustrates a known 3GPP system 100 that uses AMBR. The 3GPPsystem 100 comprises a UE 105 communicating with two independent PDNs,PDN-1 135 and PDN-2 145 via first and second access point nodes 130, 140respectively, which are shown as GWs. The respective data streams to thePDNs are routed by a Mobility Management Entity (MME) 120, which iscoupled to Authentication, Authorization and Accounting (AAA) Server125. The totality of these network elements is often referred to as acore network 115. A Node-B 110 routes the wireless transmission from theUE 105 to the MME 120 in the core network 115. In order to utilize anAMBR to limit a data amount sent to the respective PDNs, the AMBR needsto be enforced for each of the Non-Guaranteed Bit Rate (GBR) bearersconnecting the UE with a particular GW providing access to a specificPDN.

In 3GPP (see, for example, 3GPP TS 23.401, ‘GPRS enhancements forE-UTRAN access’; Release 8) the AMBR is enforced in the NodeB 110 in3GPP for the UpLink (UL) traffic and in the GW (for example PDN-1 andPDN-2 GWs in 3GPP) for the respective DownLink (DL) traffic. This is anatural choice given that the NodeB and GWs are the traffic ingresspoints for the UL and DL traffic respectively. Furthermore, as radioresources are the most cost sensitive for a wireless Operator, it is notreasonable to ‘pass through’ UL traffic over an air-interface when theUL traffic will be later discarded.

Thus, the Node B 110 has to be informed of the PDN connections that theUE 105 has established at any time and be in a position to associate theradio bearer that it assigns scheduling priorities with the UE-PDNconnection that it belongs to. In other words the Node B 110 has to takeinto account the AMBR value and its relationship with each UE-PDNconnection to the UL scheduling decisions it makes (for example byassignment of a prioritized bit rate PBR). The Node-B 110 also controlsthe radio bearer establishment and management.

According to the information received from the relevant Core Network(CN) 115 element, for example MME 120 in the 3GPP Evolved Packet System(EPS), the Node B 110 establishes the radio bearers for all thecorresponding gateways (GW).

The characteristics of AMBR are somewhat different to other dynamicbearer parameters that are used in wireless and other communicationsystems to support a particular end-to-end QoS, in the sense that:

(i) An AMBR value is applied to a ‘bundle’ of Non-GBR bearers, for aspecific UE-PDN connection, and not each one individually. Therefore,AMBR values require a special treatment by the network element that isresponsible to enforce and police the AMBR, particularly when thiselement is responsible to schedule resources that are dynamicallychanging (such as the Node-B); and

(ii) The AMBR value is static subscriber information, stored in thesubscriber database registry.

Therefore, the AMBR value has to be communicated during the initialattach procedure, instead of being dynamically provided by the PolicyServer as part of the bearer setup, in contrast to how the otherdynamically changing QoS parameters are normally provided.

FIG. 2 illustrates a known radio bearer establishment mechanism betweenthe UE 105 and the Node-B 110, and the AMBR policing performed in the ULand DL respectively.

It is noteworthy that a one-to-one relationship between the radio bearer205 that connects the UE 105 to the Node-B 110 and access bearer 210that terminates the traffic to the PDN GW 130 is maintained at the radiobearer 205 establishment. At a given time, there may be more than oneradio bearer 205 and access bearer 210 established to the UE 105 for thepurposes of providing different Quality of Service (QoS) treatment todifferent user applications or classes of users. In the DL, the logicalelements of the scheduler in the Node-B 110 schedules the DL trafficbased on a particular Quality of Service (QoS) of the radio bearers 205that has been indicated to it by some QoS identifier during the bearerestablishment as well as traffic volume used in the respective radiobearers 205. The AMBR policing for the DL traffic is carried out at therespective PDN GW 130, 135, 140, 145, given this is where the 3GPPPolicy and Charging Enforcement Function (PCEF) is typically locatedsince the PDN GWs 130, 140 are the first ingress points of downlink (DL)traffic.

If an AMBR level is exceeded in the DL, for a particular PDN connection,the exceeding traffic for all the access (non-GBR) bearers 210 from thisPDN GW may be rate limited by the 3GPP PCEF in the PDN GW, in order toconform to the specified AMBR that has been communicated to the PDN GWat the initial bearer establishment.

Thus, UL resource is assigned by the appropriate logical element of thescheduler in the Node-B 110 according to the traffic volume reported bythe UE, and allocated on a per UE basis. The scheduling of radio bearers205 into the allocated grant is performed by the UE 105 using thelogical function of the UL packet scheduler based on priorities that arecommunicated to it at the radio bearer establishment by the Node-B 110.In order to control the radio bearer scheduling by the UE 105, an ULrate control function that manages the sharing of UL resources betweenradio bearers has been specified in 3GPP. The scheduler in the Node-B110 configures each radio bearer 205 with scheduling parameters, such asan absolute priority value and a Prioritized Bit Rate (PBR) value, basedon the Quality of Service (QoS) parameters that are communicated by thecore network (CN), such as the QoS label and the GBR value for the GBRbearers. In addition, a maximum bit rate (MBR) may be optionallyconfigured per radio bearer 205. The assigned priority value and the PBRare signaled to the UE 105 together with the radio bearer configurationinformation. The priority value is decided by the Node-B 110 based onthe QoS information received from the Core Network (CN) 115.

In this manner, the PBR sets an UL rate control limit at the UE thatapplies per radio bearer and ensures that the UE 105 serves its radiobearers 205 in decreasing priority order up to their PBR value.

If any resources remain available, all the radio bearers 205 are servedin a strictly decreasing priority order, up to their MBR (ifconfigured). In a case where no MBR is configured, the radio bearer 205is served until either the data for that radio bearer 205 or the ULgrant is exhausted, whichever occurs first. In general terms theseparameters are the scheduling priority parameters that apply in the caseof a 3GPP long-term evolution (LTE) wireless communication system.

However, the inventors have recognized and appreciated that theassignment of these scheduling parameters (for example PBR, priority and(optionally) MBR in a case of a 3GPP LTE wireless communication system)are not associated with the AMBR that applies to the entire UE-PDNconnection that this radio bearer serves. This means, in effect, that iftwo bearers have the same QoS characteristics (for example, QoS label)and even though they belong to two different PDN connections (forexample one with high AMBR values and one with low AMBR values), bothradio bearers will receive the same scheduling treatment given that theAMBR is not communicated to the Node-B. Thus, this scenario isinefficient and wasteful of valuable resource. For example, if a bearerserves hyper text transfer protocol (HTTP) traffic from a virtualprivate network (VPN) with high AMBR and HTTP traffic from the Internetwith a low AMBR, the same scheduling treatment at the Node-B 110 and theUE 105 will apply to both.

Consequently, current techniques are suboptimal. Hence, an improvedmechanism to address the problem of handling AMBR over a cellularnetwork would be advantageous.

SUMMARY OF THE INVENTION

Accordingly, the invention seeks to mitigate, alleviate or eliminate oneor more of the above-mentioned disadvantages singly or in anycombination.

According to a first aspect of the invention, there is provided, amethod of signaling in a wireless communication system comprising afirst network element serving a wireless communication unit with atleast one packet data network (PDN) connection. The method comprisestransmitting, by the first network element to the wireless communicationunit, a signaling message relating to a wireless communication unituplink (UL) PDN transmission. The signaling message comprises aparameter indicative of at least one aggregate maximum bit rate (AMBR)value.

In this manner, a mechanism to police the AMBR value in the Node-Bwithout wasting unnecessarily uplink resource is provided by modifying,for example, the scheduler function in the Node-B to assign schedulingparameters relevant to the value of the UL AMBR that has to be enforcedfor radio bearers serving on UE-PDN connection.

Thus, embodiments of the invention may allow improved use of thecommunication resource by more efficiently utilizing uplink resources inthe communication system, for example, as a result of not admitting bythe Node-B uplink (UL) traffic transmitted by the UE that may have to bedropped later if it exceeded the AMBR value.

Consequently, the invention may provide increased throughput rates andincrease the capacity in the communication system by not admittingtraffic that may have to be subsequently dropped. Furthermore, theinvention may allow improved performance, as perceived by the end-users,and also may allow the network operator to increase a number of usersthat can be supported by the system, whilst still being able to controlthe UL AMBR that is transmitted by the UEs to a certain PDN connection.

According to an optional feature of the invention, the aforementionedtransmitting comprises transmitting as part of an establishment of theat least one PDN connection. In this manner, the signaling message maybe implemented within existing messages to establish at least one PDNconnection.

According to an optional feature of the invention, the signaling messagecomprises at least one AMBR value. In this manner, no association of aparameter needs to be generated by the network element may be avoided,with the AMBR value provided directly.

According, to an optional feature of the invention, the signalingmessage comprises a parameter associated with the at least one AMBRvalue. In this manner, existing signaled parameters may be modified toreflect (be associated with) the at least one AMBR value.

According to an optional feature of the invention, the method furthercomprises associating, by the first network element, a received datapacket from the wireless communication unit with a user transmissionpriority level associated with the at least one PDN connection based onthe at least one AMBR value. In this manner, an user transmissionpriority level may be associated with the at least one PDN connection toreflect (be associated with) the at least one AMBR value.

According to an optional feature of the invention, at least one PDNidentifier per PDN connection may be associated based on the at leastone AMBR value.

According to an optional feature of the invention, the method furthercomprises deriving, by the first network element, a maximum bit rate(MBR) value per PDN connection of the wireless communication unit to thefirst network element based on the at least one AMBR level.

According to an optional feature of the invention, the wirelesscommunication system further comprises a first network element operablycoupled to a second network element over a PDN connection. The methodfurther comprises transmitting, by the second network element to thefirst network element, the signaling message relating to the wirelesscommunication unit UL PDN transmission.

In this manner, an element in the core network, for example a mobilitymanagement entity (MME), may be configured to access and communicate theAMBR value, for example via a user profile of the wireless communicationunit that comprises at least one AMBR value per PDN connection.

According to an optional feature of the invention, the method furthercomprises identifying, by the first network element, when an allocationof a user transmission priority value exceeds the AMBR value applied tothe at least one PDN connection.

According to an optional feature of the invention, the method furthercomprises re-allocating, by the first network element, at least one usertransmission priority value associated with the at least one PDNconnection when the AMBR value is exceeded.

According to an optional feature of the invention, the aforementionedstep of transmitting comprises transmitting as part of an attachprocedure to establish the at least one PDN connection of the wirelesscommunication unit to the first network element. In this manner, thesignaling message may be implemented within existing messages toestablish at least one PDN connection.

In one optional embodiment, the at least one PDN connection of thewireless communication unit comprises a plurality of PDN connectionsthat the wireless communication unit has access to, for example theattach procedure may establish a plurality of PDN connections that thewireless communication unit has access to.

In one optional embodiment, the method may be applied to a 3^(rd)Generation Partnership Project (3GPP) cellular communication system. Inone optional embodiment, the method may be applied to a 3GPP EvolvedPacket System (EPS) architecture.

In one optional embodiment, the method may be applied to a WiMAXcellular communication system.

According to a second aspect of the invention, there is provided awireless communication unit adapted to perform the wirelesscommunication unit operations hereinbefore described.

According to a third aspect of the invention, there is provided anetwork element adapted to perform the network element operationshereinbefore described.

According to a fourth aspect of the invention, there is provided anetwork element arranged to provide signaling in a wirelesscommunication system to a wireless communication unit over at least onepacket data network (PDN) connection. The network element compriseslogic for transmitting a signaling message relating to a wirelesscommunication unit uplink (UL) PDN transmission to the wirelesscommunication unit wherein the signaling message comprises a parameterindicative of at least one aggregate maximum bit rate (AMBR) value.

According to a fifth aspect of the invention, there is provided awireless communication unit arranged to receive a signaling message in awireless communication system from a network element over at least onepacket data network (PDN) connection. The wireless communication unitcomprises logic for receiving a signaling message relating to an uplink(UL) PDN transmission of the wireless communication unit wherein thesignaling message comprises a parameter indicative of at least oneaggregate maximum bit rate (AMBR) value.

According to a sixth aspect of the invention, there is provided a methodof signaling in a wireless communication system comprising a firstnetwork element serving a wireless communication unit with at least onepacket data network (PDN) connection. The method comprises receiving, bythe wireless communication unit from a first network element, asignaling message relating to an uplink (UL) PDN transmission from thewireless communication unit wherein the signaling message comprises aparameter indicative of at least one aggregate maximum bit rate (AMBR)value.

According to a seventh aspect of the invention, there is provided acomputer program product comprising program code for signaling in awireless communication system from a network element to a wirelesscommunication unit over at least one packet data network (PDN)connection. The computer program product comprises program code fortransmitting a signaling message relating to a wireless communicationunit uplink (UL) PDN transmission to the wireless communication unit,wherein the signaling message comprises a parameter indicative of atleast one aggregate maximum bit rate (AMBR) value.

These and other aspects, features and advantages of the invention willbe apparent from, and elucidated with reference to, the embodimentsdescribed hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a known 3GPP system using AMBR.

FIG. 2 illustrates a known AMBR policing, taking place in the Node B forthe UL and GW for the DL traffic.

Embodiments of the invention will be described, by way of example only,with reference to the accompanying drawings, in which:

FIG. 3 illustrates a system architecture adapted in accordance with someembodiments.

FIG. 4 illustrates an attach procedure and bearer establishment inaccordance with some embodiments.

FIG. 5 illustrates an attach procedure and bearer establishment of anEPS/LTE system in accordance with some embodiments.

FIG. 6 illustrates a scheduling mechanism for the group of bearerscorresponding to the same UE-PDN connection in accordance with someembodiments.

FIG. 7 illustrates a typical computing system that may be employed toimplement processing functionality in embodiments of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The following description focuses on embodiments of the inventionapplicable to a Evolved-UMTS (Universal Mobile Telecommunication System)cellular communication system and in particular to a Evolved PacketSystem (EPS) core network (CN) architecture within a 3^(rd) generationpartnership project (3GPP) system. However, it will be appreciated thatthe invention is not limited to this particular cellular communicationsystem, but may be applied to other cellular communication systems.

Embodiments of the invention propose to obtain the AMBR parameter withits associated PDN connection identifier from a static subscriberdatabase when the communication endpoint bootstraps and attachesinitially in the network. Furthermore, and advantageously, the AMBR iscommunicated with its associated PDN connection identifier to thenetwork element that is responsible to police and enforce the AMBR perPDN connection.

In addition, some embodiments propose a network element enforcing theAMBR for a plurality of PDN connections that the communication endpoint,for example a UE, may have in place. Thus, the network element isconfigured to be responsible to serve multiple communication endpointsin an environment of dynamically changing resources.

Referring now to FIG. 3, a wireless communication system 300 is shown inoutline, in accordance with one embodiment of the invention. In thisembodiment, the wireless communication system 300 is compliant with, andcontains network elements capable of operating over, a universal mobiletelecommunication system (UMTS) air-interface. In particular, theembodiment relates to a system's architecture for an Evolved-UTRAN(E-UTRAN) wireless communication system, which is currently underdiscussion in 3GPP. This is also referred to as Long Term Evolution(LTE).

The architecture consists of radio access network (RAN) and core network(CN) elements, with the core network 304 being coupled to externalnetworks 302 named Packet Data Networks (PDNs), such as the Internet ora corporate network. The main component of the RAN is an eNodeB (anevolved NodeB) 310, 320, which is connected to the CN 304 via S1interface and to the UEs 320 via an Uu interface. The eNodeB 310, 320controls and manages the radio resource related functions. The series ofNode Bs 310, 320 typically perform lower layer processing for thenetwork, performing such functions as Medium Access Control (MAC),formatting blocks of data for transmission and physically transmittingtransport blocks to UEs 325. In addition to these functions that theNodeB's usually perform, the adapted Node Bs 310 scheduler logicalelement is additionally arranged to interact with the logical element ofthe PEF that is assigned to enforce the UL AMBR for non-GBR bearers thatbelong to a certain UE-PDN connection, in order to provide a sub-set offunctions that the 3GPP PCEF located in the PDN GW 305 implements in thedownlink (DL) such rate limiting. An additional limitation exists inthat the rate limiting function of a PEF logical element in the UL hasto meet a certain performance, and that it cannot simply ‘pass-through’the traffic over-the-air and then drop it. Hence, the adapted schedulersin the Node Bs 310 are arranged to derive adequate scheduling parametersthat will be communicated to the UE 320 based on the AMBR that has to beenforced by the logical element of a Policy Enforcement Function (PEF)located in the Node-B 310, in order to support this operation.

The CN 304 has three main components: serving GW 306, the PDN GW (PGW)305 and mobility management entity (MME) 308. The serving-GW 306controls the U-plane (user-plane) communication. The PDN-GW 305 controlsaccess to the appropriate external network (e.g. PDN). In addition tothis operation, in one embodiment, the PDN-GW 305 is arranged to policethe DL AMBR for a number of non-GBR bearers that serve this particularUE-PDN connection. The MME 308 controls the c-plane (control plane)communication, where the user mobility, paging initiation for idle modeUEs, bearer establishment, and QoS support for the default bearer arehandled by the MME 308. In addition to these operations, in oneembodiment, the MME 308 is arranged to derive, normally using databasequery mechanisms to the Home Subscriber Server (HSS) 330 with protocolssuch as DIAMETER (as in RFC3588) or RADIUS (as in RFC2865), the UL andDL AMBR values that apply to each PDN connection that the UE 320 isallowed to establish.

The UL and DL AMBR values are based on the UE's subscription profile andprovisioning information that may be stored in a static database, suchas an HSS 330 that may contain the user credentials that are used forthe UE's authentication, user class in terms of tier of service andother static information. The UL AMBR value is communicated to thelogical element of the PEF in the Node B 310 that is assigned to enforcethe UL AMBR and the DL AMBR value is communicated to the 3GPP PCEF inthe PDN GW 305 that the UE 320 initially attaches to.

E-UTRAN RAN is based on OFDMA (orthogonal frequency division multipleaccess) in downlink (DL) and SC-FDMA (single carrier frequency divisionmultiple access) in uplink (UL).the further information of radio frameformats and physical layer configuration used in E-UTRAN can be found inTS 36.211(3GPP TS 36.211 v.1.1.1 (2007-05), ‘3GPP Technicalspecification group radio access network, physical channels andmodulation (release 8)’.

The Node-Bs 310 are connected wirelessly to the UEs 325. Each Node-Bcontains one or more transceiver units 312, 322 operably coupled torespective signal processing logic 314, 324. Similarly, each of the UEscomprise transceiver unit 327 operably coupled to signal processinglogic 329 (with one UE illustrated in such detail for clarity purposesonly) and communicate with the Node B supporting communication in theirrespective location area. The system comprises many other UEs andNode-Bs, which for clarity purposes are not shown.

Signaling of AMBR Value

In accordance with one embodiment of the invention, the interactionbetween the UE 325, Node-B 310, MME 308, GW 305, 306 and AAA have beenadapted to support improved usage of AMBR signaling. In particular, theAMBR value per the UE-PDN connection, together with the PDN gatewayidentifier from the CN to the Radio access network is communicated, toadequately communicate the available PDN connections that the UE has inplace. This mechanism is described below in further detail with respectto FIG. 4.

Referring now to FIG. 4, a single signaling flow diagram is illustratedshowing the two possibilities for the end-to-end bearer establishment ina wireless communication system:

-   -   (i) UE-initiated; and    -   (ii) Network-initiated        It is noteworthy that this signaling exchange may include also a        number of other messages and other information that are not        relevant to the description of the embodiments described herein.

In step 430, the UE 325 initiates an Attach procedure by, say, sendingits temporary identity (for example the UE System Architecture Evolution(SAE)-Temporary Mobile Subscriber Identity (S-TMSI) or Packet-TemporaryMobile Subscriber Identity (P-TMSI) to the Node-B 310. In a case of anUE-initiated bearer establishment, the Access Point Name (APN) willindicate, the appropriate Gateway 420 serving the PDN that the UE 325requires to connect to.

In a case of network-initiated there is no need for the UE 325 toprovide any indication as the MME 308 will establish a connection to allthe PDNs that the UE 325 is allowed to access from its subscriptionprofile.

In step 435, the Node-B 310 derives from the temporary identity of theUE 325, for example the UE S-TMSI or P-TMSI, the appropriate MME 308that it has to forward the Attach request. In steps 440, 445 the MME 308completes the authentication procedure with the UE 325.

In step 450, the MME 308 derives the Subscriber Info of the UE 325,which includes the information on all the PDNs the UE 325 has access to.At this stage the MME 308 will have to be able to construct a table forthe UE 325, for example as illustrated in Table 1 below:

TABLE 1 UE (imsi = xxxxxyyyyyzzzzz) APN1 Ul_ambr1, dl_ambr2 APN2Ul_ambr2, dl_ambr2 APN3 Ul_ambr3, dl_ambr3

In step 455, the MME 308 creates and sends a bearer request (or requestsa bearer depending on whether it is a UE-initiated establishment or anetwork-initiated establishment) to create connection(s) to the GW(s)305, 306.

In a case of an UE-initiated establishment, given that the UE 325 wouldhave indicated in step 430 the sole. GW address through the APN that itrequires to connect to, the MME 308 will send the bearer request to thisGW 305, 306 only. The bearer request contains the DL AMBR that the GW305, 306 has to enforce for this connection.

In a case of network-initiated bearer establishment, the MME 308 sendsbearer requests to all GWs serving the PDNs that the UE 325 has accessto, as for example identified by the list of APNs it has obtained instep 450. In one embodiment, the requests contain the DL AMBRs for eachAPN that the relevant GWs have to enforce.

In step 460, the GW(s) 305, 306 create and send the bearer response(s).In case of UE-initiated only the selected GW 305, 306 that received thebearer request sends the response.

In step 465, the MME 308 sends the Attach Response to the Node-B 310containing the QoS information and the value of the UL AMBR. In a caseof an UE-initiated establishment, the Attach Response message willcontain only the information required by the particular UE PDNconnection. In a case of a network-initiated establishment, the AttachResponse message contains all the information on QoS and UL AMBRs forall the APNs that the UE has access to.

In step 470, the Node-B 310 establishes the relevant radio bearer(s),subject to the information provided in step 465. In a case of anUE-initiated establishment, this leads to the establishment of only oneradio bearer corresponding to this particular UE-PDN connection. In acase of a network-initiated establishment, the Node-B 310 at this stageestablishes all the radio bearers to serve all the required PDNconnections for the UE.

The mechanism employed by the Node-B 310 to handle the informationprovided in step 465, in order to determine scheduling parameters is asfollows.

Referring now to FIG. 5, an enhanced embodiment is described withrespect to AMBR signaling in the core network of an E-UTRAN. As definedin 3GPP TS 23.401, ‘GPRS enhancements for E-UTRAN access’; Release 8,the AMBR associated with each PDN that the UE 405 has access to isstored in the home subscriber server (HSS) (equivalent to the homelocation register in earlier GSM-based systems) based on subscriberinformation. The AMBR is retrieved by the MME 415 as part of the‘Attach’ procedure illustrated in step 430, 435 of FIG. 4.

As an example, the following information may be stored in the HSS foreach UE, as illustrated in Table 2 below:

TABLE 2 UE (imsi = xxxxxyyyyyzzzzz) APN1 Ul_ambr1, Dl_ambr2 APN2Ul_ambr2, Dl_ambr2 APN3 Ul_ambr3, Dl_ambr3

This information is retrieved in the MME 415 after the UE attaches, andshould be provided in the PDN GW 422 and eNodeB 410 for DL and ULpolicing respectively.

In this regard, the DL value of the AMBR may be sent from the MME 415 tothe PDN GW 422 as part of a ‘Create Default bearer message’, as shown instep 550, in order for the PDN GW 422 to be able to police the AMBR inthe DL. It is also envisaged, in this regard, that the UL AMBR may alsobe sent from the MME 415 to the eNodeB 410 as part of an ‘Attach Accept’message, as illustrated in step 555.

Thus, the following additional signaling is proposed to the ‘Attach’procedure of EPS/LTE as described in 3GPP TS 23.401, ‘GPRS enhancementsfor E-UTRAN access’; Release 8, to achieve the aforementionedcommunications.

The HSS 510 sends an Insert Subscriber Data message (for example IMSI,Subscription Data) to the new MME 412 in step 515. The Subscription Datacontains the Default APN and the UL and DL AMBR values for the APNs thatthe UE 405 has access to. The new MME 412 validates the UE's presence inthe (new) Tracking Area/Location Area (TA/LA). If, due to regionalsubscription restrictions or access restrictions, the UE 405 is notallowed to attach in the TA/LA, the new MME 412 may be able to rejectthe Attach Request in step 435 with an appropriate cause, and may returnan ‘Insert Subscriber Data Ack’ message 520 to the HSS 510. Ifsubscription checking fails for other reasons, the new MME 412 mayreject the Attach Request 430, 435 with an appropriate cause and returnsan Insert Subscriber Data Ack message to the HSS including an errorcause. If all checks are successful then the new MME 412 constructs acontext for the UE 405 and returns an Insert Subscriber Data Ack message520 to the HSS 510. The HSS may send an update location acknowledgemessage to the new MME 412, as shown in step 525, in accordance with theexisting process described in section 5.3.2 of 3GPP TS 23.401, ‘GPRSenhancements for E-UTRAN access’; Release 8.

In step 530 the new MME 412 selects a Serving GW 420 as described under‘GW Selection Function’, in the aforementioned standard, and sends aCreate Default Bearer Request (IMSI, MME Context ID, Default Bearer QoS,DL AMBR for the default APN) message to the selected Serving GW 420.

In step 535, the Serving GW 420 creates a new entry in its EPS Bearertable and sends a Create Default Bearer Request (Serving GW Address forthe user plane, Serving GW TEID of the user plane, Serving GW TEID ofthe control plane, Default Bearer QoS, DL AMBR for the default APN)message to the PDN GW 422.

In step 540, the PDN GW 422 may interact with the Policy and ChargingRules Function (PCRF) 505, to obtain the default policy control andcharging (PCC) rules for the UE 405, if PCRF is applied in the network.The PDN GW 422 then stores the DL AMBR for the UE 405 for the defaultbearer.

Subsequent messages 545 and 550 are sent in accordance with the existingprocess described in section 5.3.2 of 3GPP TS 23.401, ‘GPRS enhancementsfor E-UTRAN access’; Release 8.

In step 555, the new MME 412 sends an ‘Attach Accept’ (including S-TMSI,PDN address, TA/LA List) message to the eNodeB 410. S-TMSI is includedif the new MME allocates a new S-TMSI. This message may be contained inan S1_MME control message Initial Context Setup Request. This S1 controlmessage may also include a security context for the UE 405 and QoSinformation needed to set up the radio bearer, as well as the TerminalEntity Identifier (TEID) at the Serving GW 420 used for user plane andthe address of the Serving GW 420 for user plane.

The PDN address assigned to the UE 405 is included in this message. TheAPN of the PDN GW 422 that the UE 405 is connected to may also beincluded in this message. The new MME 412 sends the UL AMBR to theeNodeB 410.

In step 560, the eNodeB 410 sends a Radio Bearer Establishment Requestto the UE 405 and the Attach Accept message (S-TMSI, PDN address, TAList, APN) 555 will be sent along to the UE 405.

Thereafter, messages 565-590 are sent as described in section 5.3.2 of3GPP TS 23.401, “GPRS enhancements for E-UTRAN access”; Release 8.

AMBR Handling in the Radio Access Network, for Example the Node-B

In accordance with one embodiment of the invention, the interactionbetween the UE 325, Node-B 310, MME 308, GW 305, 306 and AAA have alsobeen adapted to support improved usage of AMBR information signaledbetween elements. In particular, apparatus and methods are proposed toallow the radio access network (RAN) to take into account theinformation provided from the Core Network (CN), to be able toprioritize traffic belonging to a particular PDN connection subject tothe AMBR. In an enhanced embodiment, apparatus and methods are alsoproposed to enforce the AMBR in the Node-B 310. The proposed mechanismconfigures the scheduler in the Node-B 310 to assign appropriatescheduling priority parameter values to the radio bearers (for example,PBR, priority values, MBR in 3GPP) in order to reflect the enforcementof the UL AMBR applied to the entire set of radio bearers correspondingto a UE-PDN connection that the PEF has to perform, in addition to thecommunicated QoS information. In addition, a mechanism is proposed tooptimize the signaling between the Node B 410 and the UE 405 (reducedsignaling overhead) to assign the scheduling priorities and amend themas and when necessary in order to police the AMBR that applies to theUE-PDN connection.

In a case where a UE 405 has multiple PDN connections, PEF logic in theNode-B 410 needs to police UL traffic belonging to each PDN connectionseparately. Therefore, the PEF logic in the Node-B 410 should have beeninformed of any association between the access bearers and the PDNconnection during the bearer establishment.

In step 470 of FIG. 4, the simplistic case of traffic policing is wherethe AMBR value of a particular PDN connection is exceeded by the ULtraffic, where the data may be dropped at the Node-B 410. However, thedata would have already been transmitted over the air-interface. Thus,dropping the already transmitted data at the Node-B 410 would result ininefficient radio resource usage.

Although embodiments of the invention are described with reference tothe MME obtaining at least one aggregate maximum bit rate (AMBR) value,and communicating this to the Node-B's PEF logic, it is envisaged thatin alternative embodiments it may be possible for the Node-B PEF logicto obtain the UL AMBR value direct. In this scenario, the Node-Bs arearranged to have a direct interface to the AAA Server (or a homesubscriber server (HSS) in a case of 3GPP systems) and perform themobility management, user authentication and QoS provisioning for thedefault bearer functions themselves. In other words, in such a scenario,all the current functions of the MME are embodied in the Node-B.

Further, although embodiments of the invention are described withreference to the MME obtaining at least one aggregate maximum bit rate(AMBR) value and communicating this to the Node-B, with the Node-Bgenerating an association of the AMBR with the at least one PDNIdentifier, it is envisaged that in alternative embodiments it may bepossible for the Node-B to obtain to transmit the AMBR value directly tothe wireless communication unit (for example the UE). In this scenario,the UE will be responsible for the policing of the UL AMBR for thenumber of radio bearers that belong to a specific UE-PDN connection. Inaddition to the AMBR, in this scenario, the information of the PDNidentifier may be communicated by the Node-B to the UE upon the radiobearer establishment. The inventors though recognize that this scenariohas a limitation that the policing of the AMBR that is associated withthe management of radio resources will be relayed solely to the UE thatis traditionally considered as an ‘un-trusted’ entity in similarcommunication systems.

AMBR Handling in the NodeB Based on Assigning Absolute Priority Per PDNConnection

Referring now to FIG. 6, a possible mechanism to perform scheduling inthe NodeB is illustrated. The mechanism is based on the AMBR values thathave been communicated as part of the bearer establishment, theIdentifier (ID) for PDN GW 422 or 424 (for example APN in 3GPP) may besignaled to the UE 405 together with the assigned scheduling priorityparameters (for example absolute priority value and PBR in 3GPP) duringthe radio bearer configuration. In addition to this signaling, anabsolute priority is also signaled to apply to the group of bearers thatare related to a specific PDN connection.

For example, the priority that applies to each radio bearer may bedefined in two steps. First, each PDN connection is provided an absolutepriority value (P_(i) 505 P_(Z) 510). Secondly, the priority of theradio bearer is assigned a relative value, relative to the absolutepriority value of the PDN connection. Thus, the UE 405 may calculate theabsolute priority value of the radio bearer by considering the absolutepriority value of the PDN connection and the relative priority of theradio bearer.

It will be appreciated that, for clarity purposes, the above descriptionhas described embodiments of the invention with reference to differentfunctional units and processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits or processors, for example with respect to the broadcast modelogic or management logic, may be used without detracting from theinvention. For example, functionality illustrated to be performed byseparate processors or controllers may be performed by the sameprocessor or controller. Hence, references to specific functional unitsare only to be seen as references to suitable means for providing thedescribed functionality, rather than indicative of a strict logical orphysical structure or organization.

Aspects of the invention may be implemented in any suitable formincluding hardware, software, firmware or any combination of these. Theinvention may optionally be implemented, at least partly, as computersoftware running on one or more data processors and/or digital signalprocessors. Thus, the elements and components of an embodiment of theinvention may be physically, functionally and logically implemented inany suitable way. Indeed, the functionality may be implemented in asingle unit, in a plurality of units or as part of other functionalunits.

FIG. 7 illustrates a typical computing system 700 that may be employedto implement processing functionality in embodiments of the invention.Computing systems of this type may be used in the UE (which may be anintegrated device, such as a mobile phone or a USB/PCMCIA modem), orNodeB (in particular, the scheduler of the NodeB), core networkelements, such as the GGSN, and RNCs, for example. Those skilled in therelevant art will also recognize how to implement the invention usingother computer systems or architectures. Computing system 700 mayrepresent, for example, a desktop, laptop or notebook computer,hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe,server, client, or any other type of special or general purposecomputing device as may be desirable or appropriate for a givenapplication or environment. Computing system 700 can include one or moreprocessors, such as a processor 704. Processor 704 can be implementedusing a general or special purpose processing engine such as, forexample, a microprocessor, microcontroller or other control logic. Inthis example, processor 704 is connected to a bus 702 or othercommunications medium.

Computing system 700 can also include a main memory 708, such as randomaccess memory (RAM) or other dynamic memory, for storing information andinstructions to be executed by processor 704. Main memory 708 also maybe used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor704. Computing system 700 may likewise include a read only memory (ROM)or other static storage device coupled to bus 702 for storing staticinformation and instructions for processor 704.

The computing system 700 may also include information storage system710, which may include, for example, a media drive 712 and a removablestorage interface 720. The media drive 712 may include a drive or othermechanism to support fixed or removable storage media, such as a harddisk drive, a floppy disk drive, a magnetic tape drive, an optical diskdrive, a compact disc (CD) or digital video drive (DVD) read or writedrive (R or RW), or other removable or fixed media drive. Storage media718 may include, for example, a hard disk, floppy disk, magnetic tape,optical disk, CD or DVD, or other fixed or removable medium that is readby and written to by media drive 714. As these examples illustrate, thestorage media 718 may include a computer-readable storage medium havingstored therein particular computer software or data.

In alternative embodiments, information storage system 710 may includeother similar components for allowing computer programs or otherinstructions or data to be loaded into computing system 700. Suchcomponents may include, for example, a removable storage unit 722 and aninterface 720, such as a program cartridge and cartridge interface, aremovable memory (for example, a flash memory or other removable memorymodule) and memory slot, and other removable storage units 722 andinterfaces 720 that allow software and data to be transferred from theremovable storage unit 718 to computing system 700.

Computing system 700 can also include a communications interface 724.Communications interface 724 can be used to allow software and data tobe transferred between computing system 700 and external devices.Examples of communications interface 724 can include a modem, a networkinterface (such as an Ethernet or other NIC card), a communications port(such as for example, a universal serial bus (USB) port), a PCMCIA slotand card, etc. Software and data transferred via communicationsinterface 724 are in the form of signals which can be electronic,electromagnetic, and optical or other signals capable of being receivedby communications interface 724. These signals are provided tocommunications interface 724 via a channel 728. This channel 728 maycarry signals and may be implemented using a wireless medium, wire orcable, fiber optics, or other communications medium. Some examples of achannel include a phone line, a cellular phone link, an RF link, anetwork interface, a local or wide area network, and othercommunications channels.

In this document, the terms ‘computer program product’‘computer-readable medium’ and the like may be used generally to referto media such as, for example, memory 708, storage device 718, orstorage unit 722. These and other forms of computer-readable media maystore one or more instructions for use by processor 704, to cause theprocessor to perform specified operations. Such instructions, generallyreferred to as ‘computer program code’ (which may be grouped in the formof computer programs or other groupings), when executed, enable thecomputing system 700 to perform functions of embodiments of the presentinvention. Note that the code may directly cause the processor toperform specified operations, be compiled to do so, and/or be combinedwith other software, hardware, and/or firmware elements (e.g., librariesfor performing standard functions) to do so.

In an embodiment where the elements are implemented using software, thesoftware may be stored in a computer-readable medium and loaded intocomputing system 700 using, for example, removable storage drive 714,drive 712 or communications interface 724. The control logic (in thisexample, software instructions or computer program code), when executedby the processor 704, causes the processor 704 to perform the functionsof the invention as described herein.

It will be appreciated that, for clarity purposes, the above descriptionhas described embodiments of the invention with reference to differentfunctional units and processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, processors or domains may be used without detracting from theinvention. For example, functionality illustrated to be performed byseparate processors or controllers may be performed by the sameprocessor or controller. Hence, references to specific functional unitsare only to be seen as references to suitable means for providing thedescribed functionality, rather than indicative of a strict logical orphysical structure or organization.

Aspects of the invention may be implemented in any suitable formincluding hardware, software, firmware or any combination of these. Theinvention may optionally be implemented, at least partly, as computersoftware running on one or more data processors and/or digital signalprocessors. Thus, the elements and components of an embodiment of theinvention may be physically, functionally and logically implemented inany suitable way. Indeed, the functionality may be implemented in asingle unit, in a plurality of units or as part of other functionalunits.

Although the invention has been described in connection with someembodiments, it is not intended to be limited to the specific form setforth herein. Rather, the scope of the present invention is limited onlyby the claims. Additionally, although a feature may appear to bedescribed in connection with particular embodiments, one skilled in theart would recognize that various features of the described embodimentsmay be combined in accordance with the invention.

Furthermore, although individually listed, a plurality of means,elements or method steps may be implemented by, for example, a singleunit or processor. Additionally, although individual features may beincluded in different claims, these may possibly be advantageouslycombined, and the inclusion in different claims does not imply that acombination of, features is not feasible and/or advantageous. Also, theinclusion of a feature in one category of claims does not imply alimitation to this category, but rather the feature may be equallyapplicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply anyspecific order in which the features must be performed and in particularthe order of individual steps in a method claim does not imply that thesteps must be performed in this order. Rather, the steps may beperformed in any suitable order. In addition, singular references do notexclude a plurality. Thus, references to ‘a’, ‘an’, ‘first’, ‘second’,etc. do not preclude a plurality.

1. A method of signaling in a wireless communication system comprising a first network element serving a wireless communication unit with at least one packet data network (PDN) connection, the method comprising: transmitting, by the first network element to the wireless communication unit, a signaling message relating to a wireless communication unit uplink (UL) PDN transmission wherein the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.
 2. The method of claim 1, wherein transmitting comprises transmitting as part of an establishment of the at least one PDN connection.
 3. The method of claim 1, wherein the signaling message comprises at least one AMBR value.
 4. The method of claim 1, wherein the signaling message comprises a parameter associated with the at least one AMBR value.
 5. The method of claim 4, further comprising associating, by the first network element, a received data packet from the wireless communication unit with a user transmission priority level associated with the at least one PDN connection based on the at least one AMBR value.
 6. The method of claim 4, further comprising associating, by the first network element, at least one PDN identifier per PDN connection based on the at least one AMBR value.
 7. The method of claim 4, further comprising, deriving, by the first network element, a maximum bit rate (MBR) value per PDN connection of the wireless communication unit to the first network element based oh the at least one AMBR level.
 8. The method of claim 4 wherein the wireless communication system further comprises a first network element operably coupled to a second network element over a PDN connection, the method further comprising transmitting, by the second network element to the first network element, the signaling message relating to the wireless communication unit UL PDN transmission.
 9. The method of claim 8 further comprising obtaining, by the second network element, a user profile of the wireless communication unit that comprises at least one AMBR value per PDN connection.
 10. The method of claim 1, further comprising identifying, by the first network element, when an allocation of a user transmission priority value exceeds the AMBR value applied to the at least one PDN connection.
 11. The method of claim 10 further comprising re-allocating, by the first network element, at least one user transmission priority value associated with the at least one PDN connection when the AMBR value is exceeded.
 12. The method of claim 1 wherein transmitting comprises transmitting as part of an attach procedure to establish the at least one PDN connection of the wireless communication unit to the first network element.
 13. The method of claim 12 wherein the attach procedure establishes a plurality of PDN connections that the wireless communication unit has access to.
 14. The method of claim 1 wherein the at least one PDN connection of the wireless communication unit comprises a plurality of PDN connections that the wireless communication unit has access to.
 15. The method of claim 1, when applied to a 3^(rd) Generation Partnership Project (3GPP) cellular communication system.
 16. The method of claim 15, when applied to a 3GPP Evolved Packet System (EPS) architecture, where the first network element is an eNodeB.
 17. The method of claim 1, when applied to a WiMAX cellular communication system.
 18. A wireless communication unit adapted to perform the wireless communication unit operations of claim
 1. 19. A network element adapted to perform the network element operations of claim
 1. 20. A network element arranged to provide signaling in a wireless communication system to a wireless communication unit over at least one packet data network (PDN) connection, the network element comprising: logic for transmitting a signaling message relating to a wireless communication unit uplink (UL) PDN transmission to the wireless communication unit wherein the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.
 21. The network element of claim 20 wherein the logic for transmitting comprises logic for transmitting as part of an establishment of the at least one PDN connection.
 22. The network element of claim 20 wherein the signaling message comprises at least one AMBR value.
 23. The network element of claim 20 wherein the signaling message comprises a parameter associated with the at least one AMBR value.
 24. The network element of claim 23 further comprising logic for associating a received data packet from the wireless communication unit with a user transmission priority level associated with the at least one PDN connection based on the at least one AMBR value.
 25. The network element of claim 23 further comprising logic for associating at least one PDN identifier per PDN connection based on the at least one AMBR value.
 26. The network element of claim 23 further comprising logic for deriving a maximum bit rate (MBR) value per PDN connection of the wireless communication unit to the network element based on the at least one AMBR level.
 27. The network element of claim 23 further comprising logic for obtaining a user profile of the wireless communication unit that comprises at least one AMBR value per PDN connection.
 28. The network element of claim 20, further comprising logic for identifying when an allocation of a user transmission priority value exceeds the AMBR value applied to the at least one PDN connection.
 29. The network element of claim 28 further comprising logic for re-allocating at least one user transmission priority value associated with the at least one PDN connection when the AMBR value is exceeded.
 30. The network element of claim 20 wherein logic for transmitting comprises logic for transmitting as part of an attach procedure to establish the at least one PDN connection of the wireless communication unit to the network element.
 31. The network element of claim 30 wherein the attach procedure establishes a plurality of PDN connections that the wireless communication unit has access to.
 32. The network element of claim 20 wherein the at least one PDN connection of the wireless communication unit comprises a plurality of PDN connections that the wireless communication unit has access to.
 33. The network element of claim 20, wherein the network element is a Node-B arranged to provide a signaling message in a 3^(rd) Generation Partnership Project (3GPP) cellular communication system.
 34. The network element of claim 33 wherein the network element is an eNode-B arranged to provide a signaling message in a 3GPP Evolved Packet System (EPS) architecture.
 35. The network element of claim 20 arranged to provide a signaling message in a WiMAX cellular communication system.
 36. A wireless communication unit arranged to receive a signaling message in a wireless communication system from a network element over at least one packet data network (PDN) connection, the wireless communication unit comprising: logic for receiving a signaling message relating to an uplink (UL) PDN transmission of the wireless communication unit wherein the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.
 37. A method of signaling in a wireless communication system comprising a first network element serving a wireless communication unit with at least one packet data network (PDN) connection, the method comprising: receiving, by the wireless communication unit from a first network element, a signaling message relating to an uplink (UL) PDN transmission from the wireless communication unit wherein the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.
 38. A computer program product comprising program code for signaling in a wireless communication system from a network element to a wireless communication unit over at least one packet data network (PDN) connection, the computer program product comprising program code for: transmitting a signaling message relating to a wireless communication unit uplink (UL) PDN transmission to the wireless communication unit wherein the signaling message comprises a parameter indicative of at least one aggregate maximum bit rate (AMBR) value.
 39. The computer program product of claim 38 wherein the program code for transmitting comprises program code for transmitting as part of an establishment of the at least one PDN connection.
 40. The computer program product of claim 38 wherein the signaling message comprises at least one AMBR value.
 41. The computer program product of claim 38 wherein the signaling message comprises a parameter associated with the at least one AMBR value.
 42. The computer program product of claim 41 further comprising program code for associating a received data packet from the wireless communication unit with a user transmission priority level associated with the at least one PDN connection based on the at least one AMBR value.
 43. The computer program product of claim 41 further comprising program code for associating at least one PDN identifier per PDN connection based on the at least one AMBR value.
 44. The computer program product of claim 41 further comprising program code for deriving a maximum bit rate (MBR) value per PDN connection of the wireless communication unit to the network element based on the at least one AMBR level.
 45. The computer program product of claim 41 further comprising program code for obtaining a user profile of the wireless communication unit that comprises at least one AMBR value per PDN connection.
 46. The computer program product of claim 38, further comprising program code for identifying when an allocation of a user transmission priority value exceeds the AMBR value applied to the at least one PDN connection.
 47. The computer program product of claim 46 further comprising program code for re-allocating at least one user transmission priority value associated with the at least one PDN connection when the AMBR value is exceeded.
 48. The computer program product of claim 38 wherein the program code for transmitting comprises program code for transmitting as part of an attach procedure to establish the at least one PDN connection of the wireless communication unit to the network element.
 49. The computer program product of claim 48 wherein the attach procedure establishes a plurality of PDN connections that the wireless communication unit has access to.
 50. The computer program product of claim 38 wherein the at least one PDN connection of the wireless communication unit comprises a plurality of PDN connections that the wireless communication unit has access to.
 51. The computer program product of claim 38 arranged to provide a signaling message in a 3^(rd) Generation Partnership Project (3GPP) cellular communication system.
 52. The computer program product of claim 38 arranged to provide a signaling message in a 3GPP Evolved Packet System (EPS) architecture.
 53. The computer program product of claim 38 arranged to provide a signaling message in a WiMAX cellular communication system. 